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Message-ID: <20200318160202.0000032c@Huawei.com>
Date: Wed, 18 Mar 2020 16:02:02 +0000
From: Jonathan Cameron <Jonathan.Cameron@...wei.com>
To: Tuan Phan <tuanphan@...amperecomputing.com>
CC: Mark Rutland <mark.rutland@....com>, <paches@...erecomputing.com>,
"Will Deacon" <will@...nel.org>, <linux-kernel@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] driver/perf: Add PMU driver for the ARM DMC-620 memory
controller.
On Tue, 17 Mar 2020 17:29:38 -0700
Tuan Phan <tuanphan@...amperecomputing.com> wrote:
> DMC-620 PMU supports total 10 counters which each is
> independently programmable to different events and can
> be started and stopped individually.
>
> DMC-620 PMU devices are named as arm_dmc620_<uid> where
> <uid> is the UID of DMC-620 PMU ACPI node. Currently, it only
> supports ACPI. Other platforms feel free to test and add
> support for device tree.
>
> Usage example:
> #perf stat -e arm_dmc620_0/clk_cycle_count/ -C 0
> Get perf event for clk_cycle_count counter.
>
> #perf stat -e arm_dmc620_0/clkdiv2_allocate,mask=0x1f,match=0x2f,
> incr=2,invert=1/ -C 0
> The above example shows how to specify mask, match, incr,
> invert parameters for clkdiv2_allocate event.
>
> Signed-off-by: Tuan Phan <tuanphan@...amperecomputing.com>
Hi Tuan,
A few fairly superficial comments from me. I wrote a spiel against
the macro magic making this harder to read but then noticed it's
just cut and paste from SPE. Oh well, I guess everyone to their
own taste.
Jonathan
> ---
> drivers/perf/Kconfig | 8 +
> drivers/perf/Makefile | 1 +
> drivers/perf/arm_dmc620_pmu.c | 836 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 845 insertions(+)
> create mode 100644 drivers/perf/arm_dmc620_pmu.c
>
> diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig
> index 09ae8a9..8c5b5cf 100644
> --- a/drivers/perf/Kconfig
> +++ b/drivers/perf/Kconfig
> @@ -129,4 +129,12 @@ config ARM_SPE_PMU
> Extension, which provides periodic sampling of operations in
> the CPU pipeline and reports this via the perf AUX interface.
>
> +config ARM_DMC620_PMU
> + bool "Enable PMU support for the ARM DMC-620 memory controller"
> + depends on ARM64 && ACPI
> + default n
> + help
> + Support for PMU events monitoring on the ARM DMC-620 memory
> + controller.
> +
> endmenu
> diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile
> index 2ebb4de..15a31ac 100644
> --- a/drivers/perf/Makefile
> +++ b/drivers/perf/Makefile
> @@ -12,3 +12,4 @@ obj-$(CONFIG_QCOM_L3_PMU) += qcom_l3_pmu.o
> obj-$(CONFIG_THUNDERX2_PMU) += thunderx2_pmu.o
> obj-$(CONFIG_XGENE_PMU) += xgene_pmu.o
> obj-$(CONFIG_ARM_SPE_PMU) += arm_spe_pmu.o
> +obj-$(CONFIG_ARM_DMC_PMU) += arm_dmc_pmu.o
> \ No newline at end of file
fix that.
> diff --git a/drivers/perf/arm_dmc620_pmu.c b/drivers/perf/arm_dmc620_pmu.c
> new file mode 100644
> index 0000000..e222bdb
> --- /dev/null
> +++ b/drivers/perf/arm_dmc620_pmu.c
> @@ -0,0 +1,836 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * ARM DMC-620 memory controller PMU driver
> + *
> + * Copyright (C) 2020 Ampere Computing LLC.
> + */
> +
> +#define PMUNAME "arm_dmc620"
> +#define DRVNAME PMUNAME "_pmu"
These should have driver specific prefix.
DMC620_PMUNAME
DMC620_DRVNAME
> +#define pr_fmt(fmt) DRVNAME ": " fmt
> +
> +#include <linux/acpi.h>
> +#include <linux/bitops.h>
> +#include <linux/cpuhotplug.h>
> +#include <linux/cpumask.h>
> +#include <linux/device.h>
> +#include <linux/errno.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/perf_event.h>
> +#include <linux/perf/arm_pmu.h>
> +#include <linux/platform_device.h>
> +#include <linux/printk.h>
> +
> +#define DMC620_CNT_MAX_PERIOD 0xffffffff
> +#define DMC620_PMU_CLKDIV2_MAX_COUNTERS 8
> +#define DMC620_PMU_CLK_MAX_COUNTERS 2
> +#define DMC620_PMU_MAX_COUNTERS \
> + (DMC620_PMU_CLKDIV2_MAX_COUNTERS + DMC620_PMU_CLK_MAX_COUNTERS)
> +
> +#define DMC620_PMU_OVERFLOW_STATUS_CLKDIV2_OFFSET 8
> +#define DMC620_PMU_OVERFLOW_STATUS_CLKDIV2_MASK \
> + (DMC620_PMU_CLKDIV2_MAX_COUNTERS - 1)
> +#define DMC620_PMU_OVERFLOW_STATUS_CLK_OFFSET 12
> +#define DMC620_PMU_OVERFLOW_STATUS_CLK_MASK \
> + (DMC620_PMU_CLK_MAX_COUNTERS - 1)
> +#define DMC620_PMU_COUNTERS_BASE_OFFSET 16
> +#define DMC620_PMU_COUNTER_MASK_31_00_OFFSET 0
> +#define DMC620_PMU_COUNTER_MASK_63_32_OFFSET 4
> +#define DMC620_PMU_COUNTER_MATCH_31_00_OFFSET 8
> +#define DMC620_PMU_COUNTER_MATCH_63_32_OFFSET 12
> +#define DMC620_PMU_COUNTER_CONTROL_OFFSET 16
> +#define DMC620_PMU_COUNTER_CONTROL_ENABLE_MASK BIT(0)
> +#define DMC620_PMU_COUNTER_CONTROL_INVERT_SHIFT 1
> +#define DMC620_PMU_COUNTER_CONTROL_EVENT_MUX (((x)&0x1f)>>2)
> +#define DMC620_PMU_COUNTER_CONTROL_EVENT_MUX_SHIFT 2
> +#define DMC620_PMU_COUNTER_CONTROL_INCR (((x)&0x1ff)>>7)
> +#define DMC620_PMU_COUNTER_CONTROL_INCR_SHIFT 7
> +#define DMC620_PMU_COUNTER_SNAPSHOT_OFFSET 24
> +#define DMC620_PMU_COUNTER_VALUE_OFFSET 32
> +#define DMC620_PMU_COUNTER_REG_BYTE_LENGTH 40
> +
> +#define DMC620_PMU_CLKDIV2_CYCLE_COUNT 0x0
> +#define DMC620_PMU_CLKDIV2_ALLOCATE 0x1
> +#define DMC620_PMU_CLKDIV2_QUEUE_DEPTH 0x2
> +#define DMC620_PMU_CLKDIV2_WAITING_FOR_WR_DATA 0x3
> +#define DMC620_PMU_CLKDIV2_READ_BACKLOG 0x4
> +#define DMC620_PMU_CLKDIV2_WAITING_FOR_MI 0x5
> +#define DMC620_PMU_CLKDIV2_HAZARD_RESOLUTION 0x6
> +#define DMC620_PMU_CLKDIV2_ENQUEUE 0x7
> +#define DMC620_PMU_CLKDIV2_ARBITRATE 0x8
> +#define DMC620_PMU_CLKDIV2_LRANK_TURNAROUND_ACTIVATE 0x9
> +#define DMC620_PMU_CLKDIV2_PRANK_TURNAROUND_ACTIVATE 0xA
> +#define DMC620_PMU_CLKDIV2_READ_DEPTH 0xB
> +#define DMC620_PMU_CLKDIV2_WRITE_DEPTH 0xC
> +#define DMC620_PMU_CLKDIV2_HIGHHIGH_QOS_DEPTH 0xD
> +#define DMC620_PMU_CLKDIV2_HIGH_QOS_DEPTH 0xE
> +#define DMC620_PMU_CLKDIV2_MEDIUM_QOS_DEPTH 0xF
> +#define DMC620_PMU_CLKDIV2_LOW_QOS_DEPTH 0x10
> +#define DMC620_PMU_CLKDIV2_ACTIVATE 0x11
> +#define DMC620_PMU_CLKDIV2_RDWR 0x12
> +#define DMC620_PMU_CLKDIV2_REFRESH 0x13
> +#define DMC620_PMU_CLKDIV2_TRAINING_REQUEST 0x14
> +#define DMC620_PMU_CLKDIV2_T_MAC_TRACKER 0x15
> +#define DMC620_PMU_CLKDIV2_BK_FSM_TRACKER 0x16
> +#define DMC620_PMU_CLKDIV2_BK_OPEN_TRACKER 0x17
> +#define DMC620_PMU_CLKDIV2_RANKS_IN_PWR_DOWN 0x18
> +#define DMC620_PMU_CLKDIV2_RANKS_IN_SREF 0x19
> +
> +#define DMC620_PMU_CLK_CYCLE_COUNTER 0x20
> +#define DMC620_PMU_CLK_REQUEST 0x21
> +#define DMC620_PMU_CLK_UPLOAD_STALL 0x22
> +#define DMC620_PMU_CLK_INDICATE_MASK 0x20
> +
> +struct arm_dmc620_pmu {
Given we think dmc620 is enough of a prefix for all the defines,
why add arm here? Quite a few of the functions have really long
names and dropping arm seems like a good start to me!
> + struct pmu pmu;
> + struct platform_device *pdev;
> +
> + void __iomem *pmu_csr;
> + int irq;
> + cpumask_t cpu;
> + struct hlist_node hotplug_node;
> +
> + /*
> + * We put all clkdiv2 and clk counters to a same array.
> + * The first DMC620_PMU_CLKDIV2_MAX_COUNTERS bits belong to
> + * clkdiv2 counters, the last DMC620_PMU_CLK_MAX_COUNTERS
> + * belong to clk counters.
> + */
> + DECLARE_BITMAP(used_mask, DMC620_PMU_MAX_COUNTERS);
> + struct perf_event *act_counter[DMC620_PMU_MAX_COUNTERS];
> +};
> +
> +#define to_dmc620_pmu(p) (container_of(p, struct arm_dmc620_pmu, pmu))
> +
> +/* Keep track of our dynamic hotplug state */
> +static enum cpuhp_state arm_dmc620_pmu_online;
> +
> +static ssize_t
> +dmc620_pmu_events_sysfs_show(struct device *dev,
> + struct device_attribute *attr, char *page)
> +{
> + struct perf_pmu_events_attr *pmu_attr;
> +
> + pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr);
> +
> + return sprintf(page, "event=0x%03llx\n", pmu_attr->id);
> +}
> +
> +#define DMC620_PMU_EVENT_ATTR(name, config) \
> + PMU_EVENT_ATTR(name, dmc620_pmu_event_attr_##name, \
> + config, dmc620_pmu_events_sysfs_show)
> +
> +/* clkdiv2 events list */
> +DMC620_PMU_EVENT_ATTR(clkdiv2_cycle_count,
> + DMC620_PMU_CLKDIV2_CYCLE_COUNT);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_allocate,
> + DMC620_PMU_CLKDIV2_ALLOCATE);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_queue_depth,
> + DMC620_PMU_CLKDIV2_QUEUE_DEPTH);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_waiting_for_wr_data,
> + DMC620_PMU_CLKDIV2_WAITING_FOR_WR_DATA);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_read_backlog,
> + DMC620_PMU_CLKDIV2_READ_BACKLOG);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_waiting_for_mi,
> + DMC620_PMU_CLKDIV2_WAITING_FOR_MI);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_hazard_resolution,
> + DMC620_PMU_CLKDIV2_HAZARD_RESOLUTION);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_enqueue,
> + DMC620_PMU_CLKDIV2_ENQUEUE);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_arbitrate,
> + DMC620_PMU_CLKDIV2_ARBITRATE);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_lrank_turnaround_activate,
> + DMC620_PMU_CLKDIV2_LRANK_TURNAROUND_ACTIVATE);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_prank_turnaround_activate,
> + DMC620_PMU_CLKDIV2_PRANK_TURNAROUND_ACTIVATE);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_read_depth,
> + DMC620_PMU_CLKDIV2_READ_DEPTH);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_write_depth,
> + DMC620_PMU_CLKDIV2_WRITE_DEPTH);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_highigh_qos_depth,
> + DMC620_PMU_CLKDIV2_HIGHHIGH_QOS_DEPTH);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_high_qos_depth,
> + DMC620_PMU_CLKDIV2_HIGH_QOS_DEPTH);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_medium_qos_depth,
> + DMC620_PMU_CLKDIV2_MEDIUM_QOS_DEPTH);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_low_qos_depth,
> + DMC620_PMU_CLKDIV2_LOW_QOS_DEPTH);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_activate,
> + DMC620_PMU_CLKDIV2_ACTIVATE);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_rdwr,
> + DMC620_PMU_CLKDIV2_RDWR);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_refresh,
> + DMC620_PMU_CLKDIV2_REFRESH);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_training_request,
> + DMC620_PMU_CLKDIV2_TRAINING_REQUEST);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_t_mac_tracker,
> + DMC620_PMU_CLKDIV2_T_MAC_TRACKER);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_bk_fsm_tracker,
> + DMC620_PMU_CLKDIV2_BK_FSM_TRACKER);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_bk_open_tracker,
> + DMC620_PMU_CLKDIV2_BK_OPEN_TRACKER);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_ranks_in_pwr_down,
> + DMC620_PMU_CLKDIV2_RANKS_IN_PWR_DOWN);
> +DMC620_PMU_EVENT_ATTR(clkdiv2_ranks_in_sref,
> + DMC620_PMU_CLKDIV2_RANKS_IN_SREF);
> +
> +/* clk events list */
> +DMC620_PMU_EVENT_ATTR(clk_cycle_count,
> + DMC620_PMU_CLK_CYCLE_COUNTER);
> +DMC620_PMU_EVENT_ATTR(clk_request,
> + DMC620_PMU_CLK_REQUEST);
> +DMC620_PMU_EVENT_ATTR(clk_upload_stall,
> + DMC620_PMU_CLK_UPLOAD_STALL);
> +
> +static struct attribute *arm_dmc620_pmu_events_attrs[] = {
> + &dmc620_pmu_event_attr_clkdiv2_cycle_count.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_allocate.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_queue_depth.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_waiting_for_wr_data.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_read_backlog.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_waiting_for_mi.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_hazard_resolution.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_enqueue.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_arbitrate.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_lrank_turnaround_activate.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_prank_turnaround_activate.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_read_depth.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_write_depth.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_highigh_qos_depth.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_high_qos_depth.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_medium_qos_depth.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_low_qos_depth.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_activate.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_rdwr.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_refresh.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_training_request.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_t_mac_tracker.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_bk_fsm_tracker.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_bk_open_tracker.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_ranks_in_pwr_down.attr.attr,
> + &dmc620_pmu_event_attr_clkdiv2_ranks_in_sref.attr.attr,
> + &dmc620_pmu_event_attr_clk_cycle_count.attr.attr,
> + &dmc620_pmu_event_attr_clk_request.attr.attr,
> + &dmc620_pmu_event_attr_clk_upload_stall.attr.attr,
> + NULL,
> +};
> +
> +static struct attribute_group arm_dmc620_pmu_events_attr_group = {
> + .name = "events",
> + .attrs = arm_dmc620_pmu_events_attrs,
> +};
> +
> +/* User ABI */
> +#define ATTR_CFG_FLD_mask_CFG config
> +#define ATTR_CFG_FLD_mask_LO 0
> +#define ATTR_CFG_FLD_mask_HI 44
> +#define ATTR_CFG_FLD_match_CFG config1
> +#define ATTR_CFG_FLD_match_LO 0
> +#define ATTR_CFG_FLD_match_HI 44
> +#define ATTR_CFG_FLD_invert_CFG config2
> +#define ATTR_CFG_FLD_invert_LO 0
> +#define ATTR_CFG_FLD_invert_HI 0
> +#define ATTR_CFG_FLD_incr_CFG config2
> +#define ATTR_CFG_FLD_incr_LO 1
> +#define ATTR_CFG_FLD_incr_HI 2
> +#define ATTR_CFG_FLD_event_CFG config2
> +#define ATTR_CFG_FLD_event_LO 3
> +#define ATTR_CFG_FLD_event_HI 8
> +
> +#define __GEN_PMU_FORMAT_ATTR(cfg, lo, hi) \
> + (lo) == (hi) ? #cfg ":" #lo "\n" : #cfg ":" #lo "-" #hi
> +
> +#define _GEN_PMU_FORMAT_ATTR(cfg, lo, hi) \
> + __GEN_PMU_FORMAT_ATTR(cfg, lo, hi)
> +
> +#define GEN_PMU_FORMAT_ATTR(name) \
> + PMU_FORMAT_ATTR(name, \
> + _GEN_PMU_FORMAT_ATTR(ATTR_CFG_FLD_##name##_CFG, \
> + ATTR_CFG_FLD_##name##_LO, \
> + ATTR_CFG_FLD_##name##_HI))
> +
> +#define _ATTR_CFG_GET_FLD(attr, cfg, lo, hi) \
> + ((((attr)->cfg) >> lo) & GENMASK(hi - lo, 0))
Hmm. I see this came form SPE pmu.
Personally I'd argue this makes the code harder to read than doing
most of it long hand. Ah well.
> +
> +#define ATTR_CFG_GET_FLD(attr, name) \
> + _ATTR_CFG_GET_FLD(attr, \
> + ATTR_CFG_FLD_##name##_CFG, \
> + ATTR_CFG_FLD_##name##_LO, \
> + ATTR_CFG_FLD_##name##_HI)
> +
> +GEN_PMU_FORMAT_ATTR(mask);
> +GEN_PMU_FORMAT_ATTR(match);
> +GEN_PMU_FORMAT_ATTR(invert);
> +GEN_PMU_FORMAT_ATTR(incr);
> +GEN_PMU_FORMAT_ATTR(event);
> +
> +static struct attribute *arm_dmc620_pmu_formats_attrs[] = {
> + &format_attr_mask.attr,
> + &format_attr_match.attr,
> + &format_attr_invert.attr,
> + &format_attr_incr.attr,
> + &format_attr_event.attr,
> + NULL,
> +};
> +
> +static struct attribute_group arm_dmc620_pmu_format_attr_group = {
> + .name = "format",
> + .attrs = arm_dmc620_pmu_formats_attrs,
> +};
> +
> +static const struct attribute_group *arm_dmc620_pmu_attr_groups[] = {
> + &arm_dmc620_pmu_events_attr_group,
> + &arm_dmc620_pmu_format_attr_group,
> + NULL,
> +};
> +
> +static inline
> +unsigned int arm_dmc620_pmu_counter_read32(struct arm_dmc620_pmu *dmc620_pmu,
> + unsigned int idx,
> + unsigned int offset)
> +{
> + return readl(dmc620_pmu->pmu_csr + DMC620_PMU_COUNTERS_BASE_OFFSET +
> + (idx * DMC620_PMU_COUNTER_REG_BYTE_LENGTH + offset));
> +}
> +
> +static inline
> +void arm_dmc620_pmu_counter_write32(struct arm_dmc620_pmu *dmc620_pmu,
given we only have 32 bit read / write, could we drop that?
void dmc620_pmu_counter_write
though that kind of sounds like we are just writing the counter.
void dmc620_pmu_creg_write maybe?
> + unsigned int idx,
> + unsigned int offset,
> + unsigned int val)
> +{
> + writel(val, dmc620_pmu->pmu_csr + DMC620_PMU_COUNTERS_BASE_OFFSET +
> + (idx * DMC620_PMU_COUNTER_REG_BYTE_LENGTH + offset));
> +}
> +
> +static
> +unsigned int arm_dmc620_event_to_counter_control(struct perf_event *event)
> +{
> + struct perf_event_attr *attr = &event->attr;
> + unsigned int reg = 0;
> +
> + reg |= ATTR_CFG_GET_FLD(attr, invert) <<
> + DMC620_PMU_COUNTER_CONTROL_INVERT_SHIFT;
> + reg |= ATTR_CFG_GET_FLD(attr, incr) <<
> + DMC620_PMU_COUNTER_CONTROL_INCR_SHIFT;
> + reg |= (ATTR_CFG_GET_FLD(attr, event) &
> + ~DMC620_PMU_CLK_INDICATE_MASK) <<
> + DMC620_PMU_COUNTER_CONTROL_EVENT_MUX_SHIFT;
> +
> + return reg;
> +}
> +
> +static int arm_dmc620_get_event_idx(struct perf_event *event)
> +{
> + struct arm_dmc620_pmu *dmc620_pmu = to_dmc620_pmu(event->pmu);
> + struct perf_event_attr *attr = &event->attr;
> + int start_idx, end_idx;
> + int idx;
> +
> + if (ATTR_CFG_GET_FLD(attr, event) & DMC620_PMU_CLK_INDICATE_MASK) {
> + /* clk events are selected */
> + start_idx = DMC620_PMU_CLKDIV2_MAX_COUNTERS;
> + end_idx = DMC620_PMU_MAX_COUNTERS;
> + } else {
> + start_idx = 0;
> + end_idx = DMC620_PMU_CLKDIV2_MAX_COUNTERS;
> + }
> +
> + for (idx = start_idx; idx < end_idx; ++idx) {
> + if (!test_and_set_bit(idx, dmc620_pmu->used_mask))
> + return idx;
> + }
> +
> + /* The counters are all in use. */
> + return -EAGAIN;
> +}
> +
> +static u64 arm_dmc620_pmu_read_counter(struct perf_event *event)
> +{
> + struct arm_dmc620_pmu *dmc620_pmu = to_dmc620_pmu(event->pmu);
> +
> + return (u64)arm_dmc620_pmu_counter_read32(dmc620_pmu,
> + event->hw.idx,
> + DMC620_PMU_COUNTER_VALUE_OFFSET);
> +}
> +
> +static void arm_dmc620_pmu_event_update(struct perf_event *event)
> +{
> + struct hw_perf_event *hwc = &event->hw;
> + u64 delta, prev_count, new_count;
> +
> + do {
> + /* We may also be called from the irq handler */
> + prev_count = local64_read(&hwc->prev_count);
> + new_count = arm_dmc620_pmu_read_counter(event);
> + } while (local64_cmpxchg(&hwc->prev_count,
> + prev_count, new_count) != prev_count);
> + delta = (new_count - prev_count) & DMC620_CNT_MAX_PERIOD;
> + local64_add(delta, &event->count);
> +}
> +
> +static void arm_dmc620_pmu_event_set_period(struct perf_event *event)
> +{
> + struct arm_dmc620_pmu *dmc620_pmu = to_dmc620_pmu(event->pmu);
> +
> + /*
> + * All DMC-620 PMU event counters are 32bit counters.
> + * To handle cases of extreme interrupt latency, we program
> + * the counter with half of the max count for the counters.
> + */
> + u64 val = DMC620_CNT_MAX_PERIOD >> 1;
> +
> + local64_set(&event->hw.prev_count, val);
> + arm_dmc620_pmu_counter_write32(dmc620_pmu,
> + event->hw.idx, DMC620_PMU_COUNTER_VALUE_OFFSET,
> + val);
> +}
> +
> +static void arm_dmc620_pmu_enable_counter(struct perf_event *event)
> +{
> + struct arm_dmc620_pmu *dmc620_pmu = to_dmc620_pmu(event->pmu);
> + unsigned int reg;
> +
> + reg = arm_dmc620_pmu_counter_read32(dmc620_pmu,
> + event->hw.idx, DMC620_PMU_COUNTER_CONTROL_OFFSET);
> + reg |= DMC620_PMU_COUNTER_CONTROL_ENABLE_MASK;
> + arm_dmc620_pmu_counter_write32(dmc620_pmu,
> + event->hw.idx, DMC620_PMU_COUNTER_CONTROL_OFFSET,
> + reg);
> +}
> +
> +static void arm_dmc620_pmu_disable_counter(struct perf_event *event)
> +{
> + struct arm_dmc620_pmu *dmc620_pmu = to_dmc620_pmu(event->pmu);
> + unsigned int reg;
> +
> + reg = arm_dmc620_pmu_counter_read32(dmc620_pmu,
> + event->hw.idx, DMC620_PMU_COUNTER_CONTROL_OFFSET);
> + reg &= ~DMC620_PMU_COUNTER_CONTROL_ENABLE_MASK;
> + arm_dmc620_pmu_counter_write32(dmc620_pmu,
> + event->hw.idx, DMC620_PMU_COUNTER_CONTROL_OFFSET,
> + reg);
> +}
> +
> +static irqreturn_t arm_dmc620_pmu_handle_irq(int irq_num, void *dev)
> +{
> + struct arm_dmc620_pmu *dmc620_pmu = dev;
> + struct perf_event *event;
> + bool handled = false;
> + unsigned long overflow_clkdiv2, overflow_clk;
> + int i;
> +
> + overflow_clkdiv2 = readl(dmc620_pmu->pmu_csr +
> + DMC620_PMU_OVERFLOW_STATUS_CLKDIV2_OFFSET);
> + overflow_clk = readl(dmc620_pmu->pmu_csr +
> + DMC620_PMU_OVERFLOW_STATUS_CLK_OFFSET);
> + if (!overflow_clkdiv2 && !overflow_clk)
> + return IRQ_NONE;
> +
> + for_each_set_bit(i, &overflow_clkdiv2,
> + DMC620_PMU_CLKDIV2_MAX_COUNTERS) {
> + /* clkdiv2 event overflow */
> + event = dmc620_pmu->act_counter[i];
> + if (!event)
> + continue;
> + arm_dmc620_pmu_disable_counter(event);
> + arm_dmc620_pmu_event_update(event);
> + arm_dmc620_pmu_event_set_period(event);
> + arm_dmc620_pmu_enable_counter(event);
> + handled = true;
> + }
> +
> + for_each_set_bit(i, &overflow_clk,
> + DMC620_PMU_CLK_MAX_COUNTERS) {
> + /* clk event overflow */
> + event = dmc620_pmu->act_counter[i +
> + DMC620_PMU_CLKDIV2_MAX_COUNTERS];
> + if (!event)
> + continue;
> + arm_dmc620_pmu_disable_counter(event);
> + arm_dmc620_pmu_event_update(event);
> + arm_dmc620_pmu_event_set_period(event);
> + arm_dmc620_pmu_enable_counter(event);
> + handled = true;
> + }
> +
> + if (overflow_clkdiv2)
> + writel(0, dmc620_pmu->pmu_csr +
> + DMC620_PMU_OVERFLOW_STATUS_CLKDIV2_OFFSET);
> + if (overflow_clk)
> + writel(0, dmc620_pmu->pmu_csr +
> + DMC620_PMU_OVERFLOW_STATUS_CLK_OFFSET);
> +
> + return IRQ_RETVAL(handled);
> +}
> +
> +static int arm_dmc620_pmu_event_init(struct perf_event *event)
> +{
> + struct arm_dmc620_pmu *dmc620_pmu = to_dmc620_pmu(event->pmu);
> + struct hw_perf_event *hwc = &event->hw;
> + struct perf_event *sibling;
> +
> + if (event->attr.type != event->pmu->type)
> + return -ENOENT;
> +
> + /*
> + * DMC 620 PMUs are shared across all cpus and cannot
> + * support task bound and sampling events.
> + */
> + if (is_sampling_event(event) ||
> + event->attach_state & PERF_ATTACH_TASK) {
> + dev_dbg(dmc620_pmu->pmu.dev,
> + "Can't support per-task counters\n");
> + return -EOPNOTSUPP;
> + }
> +
> + if (event->cpu < 0) {
> + dev_dbg(dmc620_pmu->pmu.dev,
> + "Per-task mode not supported\n");
> + return -EOPNOTSUPP;
> + }
> + /*
> + * Many perf core operations (eg. events rotation) operate on a
> + * single CPU context. This is obvious for CPU PMUs, where one
> + * expects the same sets of events being observed on all CPUs,
> + * but can lead to issues for off-core PMUs, where each
> + * event could be theoretically assigned to a different CPU. To
> + * mitigate this, we enforce CPU assignment to one, selected
> + * processor.
> + */
> + event->cpu = cpumask_first(&dmc620_pmu->cpu);
> +
> + /*
> + * We must NOT create groups containing mixed PMUs, although software
> + * events are acceptable
> + */
> + if (event->group_leader->pmu != event->pmu &&
> + !is_software_event(event->group_leader))
> + return -EINVAL;
> +
> + for_each_sibling_event(sibling, event->group_leader) {
> + if (sibling->pmu != event->pmu &&
> + !is_software_event(sibling))
> + return -EINVAL;
> + }
> +
> + hwc->idx = -1;
> + return 0;
> +}
> +
> +static void arm_dmc620_pmu_read(struct perf_event *event)
> +{
> + arm_dmc620_pmu_event_update(event);
> +}
> +
> +static void arm_dmc620_pmu_start(struct perf_event *event, int flags)
> +{
> + struct arm_dmc620_pmu *dmc620_pmu = to_dmc620_pmu(event->pmu);
> +
> + event->hw.state = 0;
> + arm_dmc620_pmu_event_set_period(event);
> +
> + if (flags & PERF_EF_RELOAD) {
> + unsigned long prev_raw_count =
> + local64_read(&event->hw.prev_count);
> +
> + arm_dmc620_pmu_counter_write32(dmc620_pmu,
> + event->hw.idx, DMC620_PMU_COUNTER_VALUE_OFFSET,
> + (unsigned int)prev_raw_count);
> + }
> + arm_dmc620_pmu_enable_counter(event);
> +}
> +
> +static void arm_dmc620_pmu_stop(struct perf_event *event, int flags)
> +{
> + if (event->hw.state & PERF_HES_STOPPED)
> + return;
> +
> + arm_dmc620_pmu_disable_counter(event);
> + arm_dmc620_pmu_event_update(event);
> + event->hw.state |= PERF_HES_STOPPED | PERF_HES_UPTODATE;
> +}
> +
> +static int arm_dmc620_pmu_add(struct perf_event *event, int flags)
> +{
> + struct arm_dmc620_pmu *dmc620_pmu = to_dmc620_pmu(event->pmu);
> + struct hw_perf_event *hwc = &event->hw;
> + struct perf_event_attr *attr = &event->attr;
> + unsigned long reg;
> + int idx = 0;
No point in assigning to 0.
> +
> + idx = arm_dmc620_get_event_idx(event);
> + if (idx < 0)
> + return idx;
> +
> + hwc->idx = idx;
> + dmc620_pmu->act_counter[idx] = event;
> + hwc->state = PERF_HES_STOPPED | PERF_HES_UPTODATE;
> +
> + /* Write to mask 31-00 register */
> + reg = ATTR_CFG_GET_FLD(attr, mask);
> + arm_dmc620_pmu_counter_write32(dmc620_pmu,
> + event->hw.idx, DMC620_PMU_COUNTER_MASK_31_00_OFFSET,
> + (unsigned int)(reg & 0xffffffff));
lower_32_bits makes it explicit what is going on.
> + /* Write to mask 63-32 register */
> + arm_dmc620_pmu_counter_write32(dmc620_pmu,
> + event->hw.idx, DMC620_PMU_COUNTER_MASK_63_32_OFFSET,
> + (unsigned int)(reg >> 32));
upper_32_bits
> +
> + /* Write to match 31-00 register */
The code for all these makes it clear what is being written.
I wouldn't leave comments around that might get out of sync if
they don't add information.
> + reg = ATTR_CFG_GET_FLD(attr, match);
> + arm_dmc620_pmu_counter_write32(dmc620_pmu,
> + event->hw.idx, DMC620_PMU_COUNTER_MATCH_31_00_OFFSET,
> + (unsigned int)(reg & 0xffffffff));
> + /* Write to match 63-32 register */
> + arm_dmc620_pmu_counter_write32(dmc620_pmu,
> + event->hw.idx, DMC620_PMU_COUNTER_MATCH_63_32_OFFSET,
> + (unsigned int)(reg >> 32));
> +
> + /* Write to control register */
> + reg = arm_dmc620_event_to_counter_control(event);
> + arm_dmc620_pmu_counter_write32(dmc620_pmu,
> + event->hw.idx, DMC620_PMU_COUNTER_CONTROL_OFFSET,
> + (unsigned int)reg);
> +
> + if (flags & PERF_EF_START)
> + arm_dmc620_pmu_start(event, PERF_EF_RELOAD);
> +
> + perf_event_update_userpage(event);
> + return 0;
> +}
> +
> +static void arm_dmc620_pmu_del(struct perf_event *event, int flags)
> +{
> + struct arm_dmc620_pmu *dmc620_pmu = to_dmc620_pmu(event->pmu);
> + struct hw_perf_event *hwc = &event->hw;
> + int idx = hwc->idx;
> +
> + arm_dmc620_pmu_stop(event, PERF_EF_UPDATE);
> + dmc620_pmu->act_counter[idx] = NULL;
> + clear_bit(idx, dmc620_pmu->used_mask);
> + perf_event_update_userpage(event);
> +}
> +
> +static int arm_dmc620_pmu_perf_init(struct arm_dmc620_pmu *dmc620_pmu)
> +{
> + struct device *dev = &dmc620_pmu->pdev->dev;
> + unsigned long long value;
> + char *name;
> + acpi_handle handle;
> + acpi_status status;
> +
> + dmc620_pmu->pmu = (struct pmu) {
> + .capabilities = PERF_PMU_CAP_NO_EXCLUDE,
> + .task_ctx_nr = perf_invalid_context,
> + .event_init = arm_dmc620_pmu_event_init,
> + .add = arm_dmc620_pmu_add,
> + .del = arm_dmc620_pmu_del,
> + .start = arm_dmc620_pmu_start,
> + .stop = arm_dmc620_pmu_stop,
> + .read = arm_dmc620_pmu_read,
> + .attr_groups = arm_dmc620_pmu_attr_groups,
> + };
> +
> + handle = ACPI_HANDLE(dev);
> + if (!handle)
> + return -ENODEV;
> +
> + status = acpi_evaluate_integer(handle, METHOD_NAME__UID, NULL,
> + &value);
> + if (ACPI_FAILURE(status)) {
> + dev_err(dev, "Failed to evaluate _UID (0x%x)\n", status);
> + return -ENODEV;
> + }
> +
> + name = devm_kasprintf(dev, GFP_KERNEL, "%s_%d", PMUNAME,
> + (unsigned int)value);
The cast implies something odd is going on. what do you loose by just making
the format string "%s_%llu"?
Hmm. This is resulting in mixture of devm and hand unwound elements. Perhaps
consider devm_add_action_or_reset to tidy that up by making everything managed.
Obviously it's fine here, but I had to check and I'm lazy (as are most
reviewers :)
> +
> + return perf_pmu_register(&dmc620_pmu->pmu, name, -1);
> +}
> +
> +static void arm_dmc620_pmu_perf_destroy(struct arm_dmc620_pmu *dmc620_pmu)
> +{
> + perf_pmu_unregister(&dmc620_pmu->pmu);
> +}
> +
> +static int arm_dmc620_pmu_cpu_startup(unsigned int cpu,
> + struct hlist_node *node)
> +{
> + struct arm_dmc620_pmu *dmc620_pmu = hlist_entry_safe(node,
> + struct arm_dmc620_pmu,
> + hotplug_node);
> +
> + dmc620_pmu = hlist_entry_safe(node, struct arm_dmc620_pmu,
> + hotplug_node);
? What is the point in the two lines above?
> + if (cpumask_empty(&dmc620_pmu->cpu))
> + cpumask_set_cpu(cpu, &dmc620_pmu->cpu);
> +
> + /* Overflow interrupt also should use the same CPU */
> + WARN_ON(irq_set_affinity(dmc620_pmu->irq, &dmc620_pmu->cpu));
> +
> + return 0;
> +}
> +
> +static int arm_dmc620_pmu_cpu_teardown(unsigned int cpu,
> + struct hlist_node *node)
> +{
> + struct arm_dmc620_pmu *dmc620_pmu = hlist_entry_safe(node,
> + struct arm_dmc620_pmu,
> + hotplug_node);
> + unsigned int target;
> +
> + if (!cpumask_test_and_clear_cpu(cpu, &dmc620_pmu->cpu))
> + return 0;
> +
> + target = cpumask_any_but(cpu_online_mask, cpu);
> + if (target >= nr_cpu_ids)
> + return 0;
> +
> + cpumask_set_cpu(target, &dmc620_pmu->cpu);
> +
> + /* Overflow interrupt also should use the same CPU */
> + WARN_ON(irq_set_affinity(dmc620_pmu->irq, &dmc620_pmu->cpu));
> +
> + return 0;
> +}
> +
> +static int arm_dmc620_pmu_dev_init(struct arm_dmc620_pmu *dmc620_pmu)
> +{
> + struct platform_device *pdev = dmc620_pmu->pdev;
> + int ret;
This feels like a wrapper function that doesn't really bring much to the
table. I'd just call the functions directly in the probe.
> +
> + ret = devm_request_irq(&pdev->dev, dmc620_pmu->irq,
> + arm_dmc620_pmu_handle_irq,
> + IRQF_SHARED,
> + dev_name(&pdev->dev), dmc620_pmu);
> + if (ret)
> + dev_err(&pdev->dev,
> + "Could not request IRQ %d\n", dmc620_pmu->irq);
> +
> + /*
> + * Register our hotplug notifier now so we don't miss any events.
> + */
> + return cpuhp_state_add_instance(arm_dmc620_pmu_online,
> + &dmc620_pmu->hotplug_node);
> +}
> +
> +static void arm_dmc620_pmu_dev_teardown(struct arm_dmc620_pmu *dmc620_pmu)
> +{
> + cpuhp_state_remove_instance(arm_dmc620_pmu_online,
> + &dmc620_pmu->hotplug_node);
> +}
> +
> +static int arm_dmc620_pmu_resource_probe(struct arm_dmc620_pmu *dmc620_pmu)
> +{
> + struct platform_device *pdev = dmc620_pmu->pdev;
> + struct resource *res;
> + int irq;
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0) {
> + dev_err(&pdev->dev, "failed to get IRQ (%d)\n", irq);
> + return -ENXIO;
Given platform_get_irq returns an error code if negative, should report
that on directly rather than ENXIO.
> + }
> + dmc620_pmu->irq = irq;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + dmc620_pmu->pmu_csr = devm_ioremap_resource(&pdev->dev, res);
devm_platform_ioremap_resource (combines the above 2 in to one call)
> + if (IS_ERR(dmc620_pmu->pmu_csr)) {
> + dev_err(&pdev->dev,
> + "ioremap failed for DMC-620 PMU resource\n");
> + return -ENXIO;
return PTR_ERR(dcm620_pmu->pmu_csr);
> + }
> +
> + return 0;
> +}
> +
> +static int arm_dmc620_pmu_device_probe(struct platform_device *pdev)
> +{
> + struct arm_dmc620_pmu *dmc620_pmu;
> + struct device *dev = &pdev->dev;
> + int ret;
> +
> + dmc620_pmu = devm_kzalloc(dev, sizeof(*dmc620_pmu), GFP_KERNEL);
> + if (!dmc620_pmu)
> + return -ENOMEM;
> +
> + dmc620_pmu->pdev = pdev;
> + platform_set_drvdata(pdev, dmc620_pmu);
> +
> + ret = arm_dmc620_pmu_resource_probe(dmc620_pmu);
> + if (ret)
> + return ret;
> +
> + ret = arm_dmc620_pmu_dev_init(dmc620_pmu);
> + if (ret)
> + return ret;
> +
> + ret = arm_dmc620_pmu_perf_init(dmc620_pmu);
> + if (ret)
> + goto out_teardown_dev;
> +
> + return 0;
> +
> +out_teardown_dev:
> + arm_dmc620_pmu_dev_teardown(dmc620_pmu);
> + return ret;
> +}
> +
> +static int arm_dmc620_pmu_device_remove(struct platform_device *pdev)
> +{
> + struct arm_dmc620_pmu *dmc620_pmu = platform_get_drvdata(pdev);
> +
> + arm_dmc620_pmu_perf_destroy(dmc620_pmu);
> + arm_dmc620_pmu_dev_teardown(dmc620_pmu);
> + return 0;
> +}
> +
> +static const struct acpi_device_id arm_dmc620_acpi_match[] = {
> + { "ARMHD620", 0},
> + {},
> +};
> +MODULE_DEVICE_TABLE(acpi, arm_dmc620_acpi_match);
> +static struct platform_driver arm_dmc620_pmu_driver = {
> + .driver = {
> + .name = DRVNAME,
> + .acpi_match_table = ACPI_PTR(arm_dmc620_acpi_match),
> + },
> + .probe = arm_dmc620_pmu_device_probe,
> + .remove = arm_dmc620_pmu_device_remove,
> +};
> +
> +static int __init arm_dmc620_pmu_init(void)
> +{
> + int ret;
> +
> + ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN, DRVNAME,
> + arm_dmc620_pmu_cpu_startup,
> + arm_dmc620_pmu_cpu_teardown);
> + if (ret < 0)
> + return ret;
> +
> + arm_dmc620_pmu_online = ret;
> +
> + ret = platform_driver_register(&arm_dmc620_pmu_driver);
> + if (ret)
> + cpuhp_remove_multi_state(arm_dmc620_pmu_online);
> +
> + return ret;
> +}
> +
> +static void __exit arm_dmc620_pmu_exit(void)
> +{
> + platform_driver_unregister(&arm_dmc620_pmu_driver);
> + cpuhp_remove_multi_state(arm_dmc620_pmu_online);
> +}
> +
> +module_init(arm_dmc620_pmu_init);
> +module_exit(arm_dmc620_pmu_exit);
> +
> +MODULE_DESCRIPTION("Perf driver for the ARM DMC-620 memory controller");
> +MODULE_AUTHOR("Tuan Phan <tuanphan@...amperecomputing.com");
> +MODULE_LICENSE("GPL v2");
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